1. Field of the Invention
The present invention relates to an apparatus, such as a camera, which is adapted to use a solar battery.
2. Description of the Related Art
Various proposals have heretofore been made with respect to a solar-battery type of portable electronic apparatus which is arranged to be driven by the electrical power generated by the solar battery. Japanese Laid-Open Patent Application No. Sho 63-160056 discloses a heat insulating or radiating structure for the body of such an electronic apparatus. According to the disclosed structure, the body of the electronic apparatus is removably provided with a secondary battery and a solar battery as an integrated component. To charge the secondary battery with energy, the secondary battery and the solar battery are removed from the body of the electronic apparatus and the solar battery is placed under the sun to generate electrical power. This is because the body of the electronic apparatus can be prevented from being overheated by direct exposure to sunlight during power generation.
Another new proposal which relates to such an electronic apparatus provided with a solar battery is disclosed in U.S. patent application Ser. No. 08/257,117 filed on Jun. 8, 1994. This proposal is intended to prevent the electronic apparatus from being overheated during power generation by a solar battery. Specifically, according to the proposal, an air layer is provided between a panel which holds a solar battery and the body of the electronic apparatus which has a built-in solar battery, whereby the body of the electronic apparatus is cooled by natural convection occurring in the air layer.
However, the structure of the related art disclosed in Japanese Laid-Open Patent Application No. Sho 63-160056 has a number of problems: (i) it is necessary to use a complicated mechanism for removably attaching a battery holder for the solar battery and the secondary battery to the body of the electronic apparatus; (ii) a contact or terminal part for providing electrical connection between the body of the electronic apparatus and the battery holder is easily contaminated to cause a conduction failure; (iii) a user may forget to remove the battery holder from the body of the electronic apparatus, with the result that not only the battery holder but also the body of the electronic apparatus may be left in direct sunshine to cause a malfunction in the body; and (iv) since the secondary battery and the solar battery are integrated, not only the solar battery but also the secondary battery is exposed to the direct rays of the sun during power generation, so that the secondary battery may be degraded and suffer a decrease in charging capacity or life. Recently, a lithium-ion battery which has characteristics suitable for use in combination with solar batteries have become popular as a secondary battery. As compared with a conventional nickel-cadmium battery, the lithium-ion battery is free from a memory effect and does not easily self-discharge, but has characteristics which are easily affected by high temperatures. For this reason, if such a lithium-ion battery is used as a secondary battery, the above-described structure itself will inherently be defective.
On the other hand, in the above-described structure proposed in U.S. patent application Ser. No. 08/257,117, since the secondary battery is built in the body of the electronic apparatus, the secondary battery is prevented from being heated by the direct rays of the sun together with the solar battery, but the body of the electronic apparatus does not have a sufficient heat insulation structure. Accordingly, to prevent the body of the electronic apparatus from being heated, it is necessary to protect not only the secondary battery but also the internal portion of the body of the electronic apparatus that is easily affected by heat.